[Bug c++/105595] New: Coroutines can trigger -Wsubobject-linkage
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105595
Bug ID: 105595
Summary: Coroutines can trigger -Wsubobject-linkage
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
Target Milestone: ---
To reproduce:
- Create a minimal coroutine promise
- Create a coroutine where any local's type has no linkage (for example a
lambda)
- #include the above from another, differently named, file
Result:
/app/not_example.cpp:25:1: warning: 'foo()::_Z3foov.Frame' has a field
'foo()::_Z3foov.Frame::anon_ns_1_2' whose type uses the anonymous namespace
[-Wsubobject-linkage]
/app/not_example.cpp:25:1: warning: 'foo()::_Z3foov.Frame' has a field
'foo()::_Z3foov.Frame::inner_class_1_2' whose type has no linkage
[-Wsubobject-linkage]
/app/not_example.cpp:25:1: warning: 'foo()::_Z3foov.Frame' has a field
'foo()::_Z3foov.Frame::a_lambda_1_2' whose type has no linkage
[-Wsubobject-linkage]
Expected:
No warning, because the coroutine frame's type shouldn't have linkage either.
Sticking anonymous types inside each other is harmless.
Full testcase:
# 2 "/app/not_example.cpp" 1
#include
class async {
public:
class promise_type {
public:
async get_return_object() { return {}; }
std::suspend_never initial_suspend() { return {}; }
std::suspend_never final_suspend() noexcept { return {}; }
void unhandled_exception() {}
};
};
namespace {
class anon_ns_t {};
}
async foo()
{
anon_ns_t anon_ns;
class inner_class_t {} inner_class;
auto a_lambda = [](){};
co_await std::suspend_never{};
}
Compile with -std=c++20.
Compiler Explorer: https://godbolt.org/z/efz6dfoWq
[Bug c++/97221] New: Returning an array unexpectedly favors const overload in return value's constructor
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97221
Bug ID: 97221
Summary: Returning an array unexpectedly favors const overload
in return value's constructor
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
Target Milestone: ---
struct string {
const char * m;
template string(const char (&str)[N]) { m = "CONST"; }
template string(char (&str)[N]) { m = "MUT"; }
};
string foo()
{
char bar[8];
return bar;
}
With Clang 10.0.1 -O2 -std=c++11, this returns "MUT".
With GCC 10.2 -O2 -std=c++98, this returns "MUT".
With GCC 7.5 -O2 -std=c++11, this returns "MUT".
With GCC 10.2 -O2 -std=c++11, this returns "CONST".
This one should give same result for every configuration, or at least throw a
warning from -Wc++11-compat, right?
Compiler Explorer: https://godbolt.org/z/r3Yo64
(Context: I encountered this when trying to make my string class distinguish
between string literals and char arrays/pointers, and call sizeof instead of
strlen for the former.)
[Bug c++/91212] [8/9/10/11 Regression] const ignored for ctor arguments within return since r8-2493-g4ce8c5dea53d8073
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91212 Alfred Agrell changed: What|Removed |Added CC||blubban at gmail dot com --- Comment #10 from Alfred Agrell --- *** Bug 97221 has been marked as a duplicate of this bug. ***
[Bug c++/97221] Returning an array unexpectedly favors const overload in return value's constructor
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97221 Alfred Agrell changed: What|Removed |Added Resolution|--- |DUPLICATE Status|UNCONFIRMED |RESOLVED --- Comment #2 from Alfred Agrell --- Ah, indeed it is. I should've checked gcc-trunk on CE, I keep forgetting it exists. Thanks, and sorry for the noise. *** This bug has been marked as a duplicate of bug 91212 ***
[Bug other/97280] New: Documentation typo - 'roudnevenl'
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97280 Bug ID: 97280 Summary: Documentation typo - 'roudnevenl' Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: other Assignee: unassigned at gcc dot gnu.org Reporter: blubban at gmail dot com Target Milestone: --- https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html "Outside strict ISO C mode [...], the functions [...] roundeven, roundevenf, roudnevenl, scalbf [...]" Should be roundevenl. It's a documentation bug only, GCC itself implements the expected name.
[Bug c++/103825] New: [12 Regression] ICE on switch on enum class in bitfield
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103825
Bug ID: 103825
Summary: [12 Regression] ICE on switch on enum class in
bitfield
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
Target Milestone: ---
enum class Type { Pawn };
struct Piece {
Type type : 4;
};
void foo() {
switch (Piece().type)
case Type::Pawn:;
}
The above causes an ICE on GCC 12.0.0 20211222, no compile flags needed. It
compiles without warnings on GCC 11, Clang, and MSVC.
Compiler Explorer: https://godbolt.org/z/GdG6ovEzz
: In function 'void foo()':
:5:6: error: type precision mismatch in switch statement
5 | void foo() {
| ^~~
switch (retval.0) , case 0: >
:5:6: internal compiler error: 'verify_gimple' failed
0x2115089 internal_error(char const*, ...)
???:0
0x11603ed verify_gimple_in_seq(gimple*)
???:0
0xdda0d1 gimplify_body(tree_node*, bool)
???:0
0xdda397 gimplify_function_tree(tree_node*)
???:0
0xbe6a57 cgraph_node::analyze()
???:0
0xbeaf6d symbol_table::finalize_compilation_unit()
???:0
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See
[Bug web/103877] New: libstdc++ docs give a bad recommendation for printing C++ defines
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103877 Bug ID: 103877 Summary: libstdc++ docs give a bad recommendation for printing C++ defines Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: web Assignee: unassigned at gcc dot gnu.org Reporter: blubban at gmail dot com Target Milestone: --- https://gcc.gnu.org/onlinedocs/libstdc++/faq.html#faq.predefined > You can also run g++ -E -dM - < /dev/null" to display a > list of predefined macros for any particular installation. Issue 1: The unmatched quote. Issue 2: g++ -E defaults to C mode, where _GNU_SOURCE is, in fact, not defined. The correct command is g++ -E -dM -xc++ - < /dev/null
[Bug libstdc++/103911] New: std::from_chars shouldn't call isdigit
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103911
Bug ID: 103911
Summary: std::from_chars shouldn't call isdigit
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
Target Milestone: ---
In header , function __from_chars_alnum calls std::isdigit().
In addition to looking weird ("everyone" knows ctype is locale dependent and
charconv is not), this can cause trouble in a handful of rare cases.
If another thread concurrently calls setlocale, that's a race condition;
additionally, if the locale contains digits other than '0'..'9', from_chars can
return wrong answer. (For example, some versions of Windows libc think 0xB2,
0xB3 and 0xB9 are the digits ²³¹ in the "us" locale.)
GCC will, by default, replace isdigit with c>='0' && c<='9'; to reproduce the
above, use -fno-builtin or Clang.
(Bonus issue: A comment on that function says it applies to bases 11 to 26.
Shouldn't that be 11 to 36?)
[Bug c++/107151] New: Specializing a concepted template can emit bogus assembly
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107151
Bug ID: 107151
Summary: Specializing a concepted template can emit bogus
assembly
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
Target Milestone: ---
#include
#include
template
void fun(T);
template <>
void fun(char c)
{
std::puts("foo()");
}
template
void fun(I i)
{
std::puts("foo()");
}
int main()
{
fun(' ');
}
Compile with -std=c++20.
Result:
/tmp/cctfBAWi.s: Assembler messages:
/tmp/cctfBAWi.s:63: Error: symbol `_Z3funIcEvT_' is already defined
/tmp/cctfBAWi.s: Error: .size expression for _Z3funIcEvT_ does not evaluate to
a constant
Expected: Prints foo(), or at least a less cryptic error. With -O2, GCC
only emits one _Z3funIcEvT_, but the resulting program prints
foo().
https://godbolt.org/z/axvdbK1Eh
Clang and MSVC have similar bugs:
https://github.com/llvm/llvm-project/issues/58142
https://developercommunity.visualstudio.com/t/Template-explicit-specializationconcept/10012835
[Bug c++/107913] New: Bogus unused variable warning if used in if constexpr false in lambda with default capture by ref
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107913
Bug ID: 107913
Summary: Bogus unused variable warning if used in if constexpr
false in lambda with default capture by ref
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
Target Milestone: ---
template
int b()
{
constexpr int c = 123;
constexpr int d = 456;
return [&](){
if constexpr (a)
return c;
else
return d;
}();
}
int g() { return b(); }
int h() { return b(); }
Compile with -Wall.
Expected result: No warnings.
Actual result:
: In instantiation of 'int b() [with bool a = true]':
:15:25: required from here
:5:19: warning: variable 'd' set but not used
[-Wunused-but-set-variable]
5 | constexpr int d = 456;
| ^
: In instantiation of 'int b() [with bool a = false]':
:16:26: required from here
:4:19: warning: variable 'c' set but not used
[-Wunused-but-set-variable]
4 | constexpr int c = 123;
| ^
The warning is very fragile, and goes away if (pick one or more)
- either variable is changed to not constexpr (oddly enough, both warnings
disappear if either variable is not constexpr)
- either variable is changed to static
- the if is changed to not constexpr
- the lambda is removed
- the variables are captured explicitly
- the lambda's default capture is by-value
(The bug does reproduce if the template is removed and changed to if constexpr
(true), but I feel the current form better demonstrates that the warning is
inappropriate.)
https://godbolt.org/z/T9nnzjj91
[Bug c++/103871] [11/12/13 Regression] co_await causes build error
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103871
Alfred Agrell changed:
What|Removed |Added
CC||blubban at gmail dot com
--- Comment #15 from Alfred Agrell ---
Just ran into this (and/or bug 98056). Still exists as of trunk-20220522.
Minimized to https://godbolt.org/z/qhWWzKe4M
#include
#include
class my_coro {
public:
my_coro();
class promise_type {
public:
my_coro get_return_object();
std::suspend_never initial_suspend();
std::suspend_never final_suspend() noexcept;
void unhandled_exception();
};
};
std::suspend_never inner(std::initializer_list);
my_coro doesnt_work()
{
co_await inner({ 1,2,3 });
}
[Bug c++/105804] New: List-initialized argument in await expression is doubly freed
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105804
Bug ID: 105804
Summary: List-initialized argument in await expression is
doubly freed
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
Target Milestone: ---
#include
#include
struct my_params {
std::unique_ptr ptr; // or any other object with nontrivial dtor
};
static std::suspend_never take_params(my_params params)
{
return {};
}
struct coro_t {
struct promise_type {
coro_t get_return_object() { return {}; }
std::suspend_never initial_suspend() { return {}; }
std::suspend_never final_suspend() noexcept { return {}; }
void unhandled_exception() noexcept {}
};
};
static coro_t my_coro()
{
co_await take_params({ std::make_unique(5) });
}
int main()
{
my_coro();
}
Expected output: Same as /bin/true
Actual: free(): double free detected in tcache 2
https://godbolt.org/z/8f9d3TzYo
Probably same root cause as bug 98056 and/or bug 103871, but since the symptoms
are way different (it's a wrong-code, not just rejects-valid), I think it
warrants a separate report.
[Bug c++/106541] New: Missing -Wuninitialized on self initialization if external code is called earlier in the function
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106541
Bug ID: 106541
Summary: Missing -Wuninitialized on self initialization if
external code is called earlier in the function
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
Target Milestone: ---
struct my_class {
int data[4];
};
void fn1();
void fn2()
{
my_class local = local;
}
void fn3()
{
fn1();
my_class local = local;
}
Compile with g++ -Wall.
Expected: Two warnings. Or maybe zero, if this is not considered a use.
Actual: Former complains, latter does not. That extra function call should not
affect the warning count.
https://godbolt.org/z/vhdnq1Ec1
[Bug sanitizer/101758] New: Inconsistent optimizations with UBSan
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101758
Bug ID: 101758
Summary: Inconsistent optimizations with UBSan
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: sanitizer
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
jakub at gcc dot gnu.org, kcc at gcc dot gnu.org, marxin at
gcc dot gnu.org
Target Milestone: ---
Input:
gcc -fsanitize=undefined -O2 -fno-strict-aliasing -Wall
float b(unsigned a) { return *(float*)&a; }
float c(unsigned a) { return *(float*)&a; }
float d(unsigned a) { return *(float*)&a; }
Output:
b:
mov DWORD PTR [rsp-4], edi
movss xmm0, DWORD PTR [rsp-4]
ret
c:
movdxmm0, edi
ret
d:
movdxmm0, edi
ret
or, on ARM
b:
sub sp, sp, #8
str r0, [sp, #4]
vldr.32 s0, [sp, #4]
add sp, sp, #8
bx lr
c:
sub sp, sp, #8
vmovs0, r0
add sp, sp, #8
bx lr
d:
sub sp, sp, #8
vmovs0, r0
add sp, sp, #8
bx lr
Expected output:
Same assembly for all three. And maybe don't set up an unused stack frame on
ARM (it's correctly optimized out without UBSan).
Compiler Explorer: https://godbolt.org/z/Tfs5qazqM
(Found it while trying to determine if that function is a strict aliasing
violation (it is), and whether it can be fixed with memcpy or a union (both
work).)
[Bug c++/102120] New: expected tree that contains 'decl common' structure, have 'identifier_node' in dump_aggr_type, at cp/error.c:786
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102120
Bug ID: 102120
Summary: expected tree that contains 'decl common' structure,
have 'identifier_node' in dump_aggr_type, at
cp/error.c:786
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
Target Milestone: ---
Input:
union U {
int value;
constexpr ~U() noexcept { }
};
constexpr int z() {
U* array = new U[5];
int result = array[3].value;
delete[] array;
return result;
}
constexpr int zz = z();
Compile with -std=c++20.
Expected output (I get this if I remove the union's dtor, or change the array
to a single object):
:13:21: in 'constexpr' expansion of 'z()'
:13:22: error: the content of uninitialized storage is not usable in a
constant expression
13 | constexpr int zz = z();
| ^
:7:23: note: allocated here
7 | U* array = new U[5];
| ^
Actual output on GCC 11.2:
'
:13: confused by earlier errors, bailing out
Yes, those two lines are the entirety of its output.
GCC trunk is slightly better, but still asks for a bug report:
'
:13:21: in 'constexpr' expansion of 'z()'
tree check: expected tree that contains 'decl common' structure, have
'identifier_node' in dump_aggr_type, at cp/error.c:786
13 | constexpr int zz = z();
| ^
0x1f30289 internal_error(char const*, ...)
???:0
0x6bb645 tree_contains_struct_check_failed(tree_node const*,
tree_node_structure_enum, char const*, int, char const*)
???:0
0x1f4c781 pp_format(pretty_printer*, text_info*)
???:0
0x1f2eeb5 diagnostic_report_diagnostic(diagnostic_context*, diagnostic_info*)
???:0
0x1f2fde9 error(char const*, ...)
???:0
0xae3d0a store_init_value(tree_node*, tree_node*, vec**, int)
???:0
0x89b0c9 cp_finish_decl(tree_node*, tree_node*, bool, tree_node*, int)
???:0
0x9d09a5 c_parse_file()
???:0
0xb55af2 c_common_parse_file()
???:0
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See
[Bug c++/102198] New: Unused and nonsensical template instantiations used for return type inference end up in the output
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102198
Bug ID: 102198
Summary: Unused and nonsensical template instantiations used
for return type inference end up in the output
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
Target Milestone: ---
Input:
template
int* a() { return x; }
template
auto b() { return a; }
template
auto c() -> int* (*)()
{
static int x1;
return b<&x1>();
}
int main(int argc, char** argv)
{
if constexpr (false)
{
static int x2;
b<&x2>();
}
c();
c();
}
Compile with -O0.
Expected output: Compiles and links successfully.
Actual output, as of 7.2 through 11.2: Assembly output contains four
instantiations of a(), using template arguments c::x1, c::x1,
main::x2, and c::x1 (or whatever _ZZ1cIXT_EEPFPivEvE2x1 is
supposed to be, c++filt doesn't like it). There's no storage assigned for the
latter two, so they instantiations throw linker errors.
/opt/compiler-explorer/gcc-11.2.0/bin/../lib/gcc/x86_64-linux-gnu/11.2.0/../../../../x86_64-linux-gnu/bin/ld:
/tmp/cc2i7eNg.o: in function `_Z1aIXadL_ZZ1cIXT_EEPFPivEvE2x1EEES1_v':
:2: undefined reference to `_ZZ1cIXT_EEPFPivEvE2x1'
/opt/compiler-explorer/gcc-11.2.0/bin/../lib/gcc/x86_64-linux-gnu/11.2.0/../../../../x86_64-linux-gnu/bin/ld:
/tmp/cc2i7eNg.o: in function `int* a<&(main::x2)>()':
:2: undefined reference to `main::x2'
collect2: error: ld returned 1 exit status
Actual output, as of current trunk:
: In instantiation of 'auto b() [with int* x = (& x1)]':
:5:6: required from here
:5:6: internal compiler error: in discriminator_for_local_entity, at
cp/mangle.c:1965
5 | auto b() { return a; }
| ^
0x1f31a39 internal_error(char const*, ...)
???:0
0x79e1c7 fancy_abort(char const*, int, char const*)
???:0
0x8fe32b mangle_decl(tree_node*)
???:0
0x148f6b2 decl_assembler_name(tree_node*)
???:0
0x14c15d0 assign_assembler_name_if_needed(tree_node*)
???:0
0xc38855 cgraph_node::analyze()
???:0
0xc3cfdd symbol_table::finalize_compilation_unit()
???:0
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See
[Bug c++/105804] coroutines: List-initialized argument in await expression is doubly freed
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105804 Alfred Agrell changed: What|Removed |Added Status|UNCONFIRMED |RESOLVED Resolution|--- |FIXED --- Comment #1 from Alfred Agrell --- Looks like this one was fixed at some point. Probably by commit r13-6702-gea4dd8f512979db247c54d6b41377bb73699bcd7, as reported in bug 103871. Good job, GCC team.
[Bug c++/114167] New: Capturing a auto..., then unpacking it in a lambda taking Ts..., confuses GCC
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114167
Bug ID: 114167
Summary: Capturing a auto..., then unpacking it in a lambda
taking Ts..., confuses GCC
Product: gcc
Version: 13.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
Target Milestone: ---
void a(int, int) {}
template
void b()
{
[](auto... ch){
[ch...](Ts... newvals) {
(a(ch, newvals), ...);
}(3,4);
}(1,2);
}
void c()
{
b();
}
No flags needed. (Needs -std=c++17, but that's the default.)
Expected: Should compile.
Actual:
: In instantiation of 'a():: [with auto:1
= {int, int}]':
:8:6: required from 'void a() [with Ts = {int, int}]'
:13:15: required from here
:6:19: error: 'newvals#0' is not captured
6 | ((ch, newvals), ...);
| ^~~
:5:9: note: the lambda has no capture-default
5 | [ch...](Ts... newvals) {
| ^~~~
6 | ((ch, newvals), ...);
| ~
7 | }(3,4);
| ~
:5:19: note: 'int newvals#0' declared here
5 | [ch...](Ts... newvals) {
| ~~^~~
Compiler returned: 1
I'm not 100% sure if that is valid C++, but Clang accepts it, and the error
message somehow manages to ask to capture newvals before it's declared.
https://godbolt.org/z/G8Kh9rvYc
[Bug target/107337] -march docs for nocona are missing CX16
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107337 Alfred Agrell changed: What|Removed |Added CC||blubban at gmail dot com --- Comment #3 from Alfred Agrell --- This bug still exists. In addition to nocona, it also affects bonnell, sierraforest, grandridge, clearwaterforest, alderlake, arrowlake, arrowlake-s, pantherlake, and amdfam10 aka barcelona.
[Bug c++/115318] New: decltype(lambda) with some templates causes ICE
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115318
Bug ID: 115318
Summary: decltype(lambda) with some templates causes ICE
Product: gcc
Version: 14.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
Target Milestone: ---
template struct S {};
template
void foo()
{
using foo_t = decltype([](){});
[]() { S{}; }();
}
void bar() { foo(); }
-std=c++20
: In instantiation of 'foo<>():: [with int k = 6]':
:7:36: required from 'void foo() [with int i = 4]'
7 | []() { S{}; }();
| ~~~^~
:10:17: required from here
10 | void bar() { foo(); }
| ~~~^~
:6:28: internal compiler error: in tsubst, at cp/pt.cc:16401
6 | using foo_t = decltype([](){});
|^~
0x202ef4c internal_error(char const*, ...)
???:0
0x778915 fancy_abort(char const*, int, char const*)
???:0
0x938dd0 tsubst(tree_node*, tree_node*, int, tree_node*)
???:0
0x943a11 tsubst_lambda_expr(tree_node*, tree_node*, int, tree_node*)
???:0
0x939200 tsubst(tree_node*, tree_node*, int, tree_node*)
???:0
0x93c437 tsubst_template_args(tree_node*, tree_node*, int, tree_node*)
???:0
0x931a0f instantiate_decl(tree_node*, bool, bool)
???:0
0x831fb7 maybe_instantiate_decl(tree_node*)
???:0
0x8332f7 mark_used(tree_node*, int)
???:0
0x7a20a3 build_op_call(tree_node*, vec**, int)
???:0
0x9602fe finish_call_expr(tree_node*, vec**, bool,
bool, int)
???:0
0x931a0f instantiate_decl(tree_node*, bool, bool)
???:0
0x94d2e3 instantiate_pending_templates(int)
???:0
0x835608 c_parse_final_cleanups()
???:0
0xa0c508 c_common_parse_file()
???:0
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See
[Bug c++/115319] New: ICE when mutating a captured parameter in an explicit-this lambda if a capture is not trivially copyable
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115319
Bug ID: 115319
Summary: ICE when mutating a captured parameter in an
explicit-this lambda if a capture is not trivially
copyable
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
Target Milestone: ---
struct S
{
S() {}
S(const S&) {}
};
void a()
{
[i=0, x=S{}](this auto self) -> void
{
i++;
}();
}
-std=c++23 (optional, it throws a c++23-extensions warning and the same ICE
without it)
: In lambda function:
:11:9: internal compiler error: in gimplify_compound_lval, at
gimplify.cc:3576
11 | i++;
| ^
0x202ef4c internal_error(char const*, ...)
???:0
0x778915 fancy_abort(char const*, int, char const*)
???:0
0xc4c739 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
???:0
0xc55a00 gimplify_self_mod_expr(tree_node**, gimple**, gimple**, bool,
tree_node*)
???:0
0xc4cf52 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
???:0
0xc4e8c4 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
???:0
0xc4ca8d gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
???:0
0xc4e8ae gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
???:0
0xc50e8e gimplify_body(tree_node*, bool)
???:0
0xc51250 gimplify_function_tree(tree_node*)
???:0
0xaba647 cgraph_node::analyze()
???:0
0xabd9b1 symbol_table::finalize_compilation_unit()
???:0
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See
[Bug c++/115331] New: [15 regression] ICE-on-invalid passing a typoed lambda to a list-initializer
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115331
Bug ID: 115331
Summary: [15 regression] ICE-on-invalid passing a typoed lambda
to a list-initializer
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
Target Milestone: ---
struct has_ctor
{
has_ctor(auto arg) {}
};
void aaa()
{
has_ctor{[]<(){}}; // typo intentional
}
-std=c++20
: In function 'void aaa()':
:8:17: error: expected identifier before '(' token
8 | has_ctor{[]<(){}};
| ^
:8:19: error: expected '>' before '{' token
8 | has_ctor{[]<(){}};
| ^
: In instantiation of 'has_ctor::has_ctor(auto:1) [with auto:1 =
aaa()::]':
:3:5: required from here
3 | has_ctor(auto arg) {}
| ^~~~
:3:5: internal compiler error: tree check: expected tree that contains
'decl common' structure, have 'error_mark' in decl_template_parm_check, at
cp/cp-tree.h:5138
0x269996c internal_error(char const*, ...)
???:0
0x96eb0f tree_contains_struct_check_failed(tree_node const*,
tree_node_structure_enum, char const*, int, char const*)
???:0
0xba20c6 mangle_decl(tree_node*)
???:0
0x16c5fc5 decl_assembler_name(tree_node*)
???:0
0x16eea01 assign_assembler_name_if_needed(tree_node*)
???:0
0xe8c11d cgraph_node::analyze()
???:0
0xe8f6d1 symbol_table::finalize_compilation_unit()
???:0
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See
[Bug c++/115364] New: ICE-on-invalid when calling non-const template member on const object
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115364
Bug ID: 115364
Summary: ICE-on-invalid when calling non-const template member
on const object
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
Target Milestone: ---
struct foo
{
template void not_const() {}
};
void fn(const foo& obj) { obj.not_const<5>(); }
No flags needed.
: In member function 'void foo::fn() const':
:4:41: error: cannot convert 'const foo*' to 'foo*'
4 | void fn() const { this->not_const<5>(); }
| ~~^~
:4:41: internal compiler error: tree check: expected function_decl,
have template_decl in get_fndecl_argument_location, at cp/call.cc:8354
0x26aa1ac internal_error(char const*, ...)
???:0
0x96fd9e tree_check_failed(tree_node const*, char const*, int, char const*,
...)
???:0
0xa7d15f complain_about_bad_argument(unsigned int, tree_node*, tree_node*,
tree_node*, int)
???:0
0xa8c20a build_new_method_call(tree_node*, tree_node*, vec**, tree_node*, int, tree_node**, int)
???:0
0xce8267 finish_call_expr(tree_node*, vec**, bool,
bool, int)
???:0
0xc6a70a c_parse_file()
???:0
0xdbfcf9 c_common_parse_file()
???:0
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See
[Bug tree-optimization/115423] New: Inlined strcmp optimizes poorly
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115423
Bug ID: 115423
Summary: Inlined strcmp optimizes poorly
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
Target Milestone: ---
bool g(const char* c) {
return __builtin_strcmp(c, ".") == 0 ||
__builtin_strcmp(c, "..") == 0;
}
bool h(const char* c) {
return (c[0] == '.' && c[1] == '\0') ||
(c[0] == '.' && c[1] == '.' && c[2] == '\0');
}
Compile with -O2.
Expected result: Same output from both.
Actual: The former results in a mess that, among other inefficiencies, loads
c[0] twice.
Online reproducer: https://godbolt.org/z/E4vEshvcM
(I don't know if this is an RTL or tree optimizer issue, I just guessed. Feel
free to move it if it's wrong.)
[Bug tree-optimization/115423] Inlined strcmp optimizes poorly
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115423
--- Comment #3 from Alfred Agrell ---
strcmp (c, "ABCDEFGHabcdefgh") || strcmp (c, "ABCDEFGHfoobar") can safely be
optimized to 1, you're thinking of strcmp(c, "ABCDEFGHabcdefgh")==0 ||
strcmp(c, "ABCDEFGHfoobar")==0.
Optimizing to multi-byte reads would be a wrong-code. If strcmp(c, "1234567")
does an eight-byte read, it'll segfault if c is {'e',0} four bytes before an
unmapped page.
Even if limiting it to aligned reads (can't segfault without crossing a page),
it'll annoy Valgrind.
(Large reads would be safe if lhs is char[8] and not char*, or if strlen is
checked before doing those reads, but both of those feel unlikely to me.)
[Bug c++/115318] decltype(lambda) from an template function inside a templated lambda causes ICE
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115318
--- Comment #2 from Alfred Agrell ---
struct a { int c; };
template
struct ddd {
int f()
{
using a2 = decltype([](int a::*)->a{}(&a::c));
return [](int a2::*){ return 2; }(&a::c);
}
};
int xs() { return ddd().f(); }
-std=c++20 again
-> :8:16: sorry, unimplemented: mangling offset_ref
https://godbolt.org/z/4M3ToqqPW
Adding a to the first lambda changes the error to the same ICE as this
issue (https://godbolt.org/z/Pq9T16GvP), so I'm about 98% sure it's the same
root cause.
[Bug c++/105667] [C++20] lambas in template argument sometimes causes an ICE (seg fault)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105667
Alfred Agrell changed:
What|Removed |Added
CC||blubban at gmail dot com
--- Comment #8 from Alfred Agrell ---
I ran into something similar. My reduced testcase is
struct class1
{
virtual void a_function() = 0;
};
template() {}>
class class2 {};
template
struct class3 : public class1 {
void a_function()
{
class2<> x;
}
};
struct class4 : public class3 {
class4() {}
};
https://godbolt.org/z/GKo5oWe8j
[Bug c++/110565] New: Incomplete note on why initializing int& with int is ill-formed
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110565
Bug ID: 110565
Summary: Incomplete note on why initializing int& with int is
ill-formed
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
Target Milestone: ---
struct X {
X(int&);
X(X&&) = delete; // the issue reproduces without this line, but the error
is clearer with it
};
template
void f() {
new X(0);
}
Expected output:
: In function 'void f()':
:8:12: error: no matching function for call to 'X::X(int)'
8 | new X(0);
|^
:2:5: note: candidate: 'X::X(int&)' (near match)
2 | X(int&);
| ^
:2:5: note: conversion of argument 1 would be ill-formed:
:8:11: error: cannot bind non-const lvalue reference of type 'int&' to
an rvalue of type 'int'
Actual output:
: In function 'void f()':
:8:12: error: no matching function for call to 'X::X(int)'
8 | new X(0);
|^
:2:5: note: candidate: 'X::X(int&)' (near match)
2 | X(int&);
| ^
:2:5: note: conversion of argument 1 would be ill-formed:
The template and new-expression are necessary; the error is proper without
them.
https://godbolt.org/z/c1Er5nsjd
[Bug libstdc++/112564] New: std::format(std::thread::id) is incorrectly left-aligned
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112564 Bug ID: 112564 Summary: std::format(std::thread::id) is incorrectly left-aligned Product: gcc Version: 14.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: libstdc++ Assignee: unassigned at gcc dot gnu.org Reporter: blubban at gmail dot com Target Milestone: --- https://godbolt.org/z/zra9GddY3 N4964 [thread.thread.id]/12 "If the align option is omitted it defaults to >." Both MSVC and libc++ right-align thread::id here as mandated by that paragraph, but libstdc++ is left-aligning. I am not sure how duration should be aligned by default but either libstdc++ or libc++ are buggy here. Found by https://github.com/StephanTLavavej
[Bug c++/116584] New: Type/value mismatch confuses error recovery
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116584
Bug ID: 116584
Summary: Type/value mismatch confuses error recovery
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: blubban at gmail dot com
Target Milestone: ---
template struct foo;
void* bar()
{
return (decltype(foo<5>)*)5;
}
No flags needed.
Result:
: In function 'void* bar()':
:5:31: error: type/value mismatch at argument 1 in template parameter
list for 'template struct foo'
5 | return (decltype(foo<5>)*)5;
| ^
:5:31: note: expected a type, got '5'
:5:17: error: expected primary-expression before 'decltype'
5 | return (decltype(foo<5>)*)5;
| ^~~~
:5:17: error: expected ')' before 'decltype'
5 | return (decltype(foo<5>)*)5;
|~^~~~
| )
Compiler returned: 1
Expected: Just the first error, the last one looks like it's telling me to
write return ();
Diagnostics are even funnier if colored - in the last one, the first letter of
decltype is red, while the ecltype is green. https://godbolt.org/z/7bcazrPsY
